A 72-year-old former postman says he brought life back to the grey seams between his tiles with kitchen-cupboard basics. He used a thick baking soda paste, a soft brush, and time. No bleach. No sting in the throat. Just steady work and a calm room.
The Norfolk retiree and the £1 paste
Peter Cooper spent three decades walking letters through wind and drizzle. Now, from his 1989 bathroom in Norfolk, he has sparked chatter for something far gentler: a £1 box of baking soda mixed into a paste that makes grout look like itself again. He works line by line with an old toothbrush and the patience that once kept his rounds on time.
The appeal sits in the plainness. He says the smell of supermarket gels lingered longer than their shine. Chlorine brightened for a week, then left the rubber trims brittle. So he reached for the simple powder his mother favoured. He found rhythm. He counted, he scrubbed, he wiped. The lines cleared without drama.
3:1 baking soda to warm water, 10–15 minutes to dwell, then a soft-bristle scrub: colour returns without harsh fumes.
What makes the paste work
Sodium bicarbonate is mildly alkaline and slightly gritty. Those two traits matter. The alkalinity loosens body oils and soap film. The fine particles lift residue without biting into the grout. That means you do not “bleach” the lines whiter than they should be; you reveal the original shade that hard water and steam had dulled.
On lines with stubborn shadowing, a light mist of white vinegar on top of the paste adds a fizz that helps break films. For patches tinted by mould, a few drops of 3% hydrogen peroxide in the paste can help. Let it sit. Wipe thoroughly. Always rinse the cloth and wipe again. The finish looks natural rather than chalked over.
Step-by-step you can copy
- Measure 3 heaped tablespoons baking soda and 1 tablespoon warm water. Stir to a toothpaste-like paste.
- Apply along grout with a fingertip or a blunt butter knife. Keep the layer even and neat.
- Leave for 10–15 minutes. Resist the urge to over-wet; the paste should cling.
- Scrub with a soft old toothbrush in short strokes. Work in small sections.
- Wipe with a damp microfibre cloth. Rinse the cloth and wipe again to lift the film.
- For extra help, lightly mist vinegar after the dwell, or add a few drops of 3% hydrogen peroxide to the paste on mouldy spots.
- Dry the lines with a clean towel. Run the fan or open a window.
Safety and what to avoid
- Never mix baking soda with bleach. Do not combine vinegar with bleach either.
- Avoid abrasive pads that scratch glazed tiles and soften grout edges.
- Skip vinegar on marble, limestone or other acid-sensitive stone. Use only the soda-and-water paste there.
- Test in a discreet corner on dyed grout to check for any lightening.
Keep the paste thick, keep the pressure light, and keep your wipe stage thorough. That is where the result appears.
What it costs, what you gain
A standard 500 g box of baking soda costs around £0.60–£1.20. A bathroom session uses roughly 30–60 g, or £0.04–£0.14. Add a few pennies for water and a fresh cloth wash. Many gels and sprays cost £3–£5 per bottle and carry harsh scents that demand open windows. The soda method trades perfume for clean air and control.
Time matters too. Peter blocks out 30 minutes every few weeks. He does not chase perfection. He keeps the lines serviceable and the room pleasant. That is achievable for most households, even in busy weeks. For families with daily showers and little ventilation, a quick fortnightly touch-up helps.
| Method | Approximate cost per session | Time | Smell | Risk to grout |
|---|---|---|---|---|
| Baking soda paste (3:1) | £0.04–£0.14 | 30 minutes | Neutral | Low when wiped well |
| Chlorine bleach gel | £0.30–£0.80 | 15–25 minutes | Strong, lingering | Can weaken edges, fade trims |
| Branded tile foam | £0.50–£1.00 | 20–30 minutes | Perfumed | Medium; depends on formula |
Why people are paying attention
This method fits a mood. Homes are seeking less plastic, fewer heavy scents, and small routines that actually stick. A paste you mix in a jar reads as honest and low-stakes. It is gentle on lungs, gentle on budgets, and gentle on the tiles themselves. There is also a psychological lift: a short, repeatable task that improves a room in one sitting.
When stains dig in
Black mould thrives where steam lingers and air stands still. If it resists the basic paste, spot-treat with a paste moistened by a few drops of 3% hydrogen peroxide. Leave for 10 minutes, scrub lightly, then rinse and dry. Repeat over several days rather than attacking hard in one go. Keep the fan running during showers and wipe water off tiles to slow the return.
Maintenance rhythm you can keep
- Frequency: every 3–4 weeks for most homes; fortnightly in high-use family bathrooms.
- Daily quick win: squeegee or towel-dry tiles after the last shower.
- Ventilation: open a window or run an extractor for 20 minutes post-shower.
- Spill control: wipe shampoo drips quickly; they feed the grey film.
Beyond grout: uses and limits for baking soda
The same paste dulls haze on shower glass and lifts tea-tinted marks from ceramic sinks. It freshens silicone seals when used without force. It also cleans oven doors when left to dwell and wiped patiently. Yet it is not universal. Skip it on lacquered wood, avoid vinegar on stone, and do not push gritty paste into polished metal that scratches easily.
Thinking ahead: sealing and long-term durability
Clean grout holds its look longer when sealed. Let lines dry for 24 hours after cleaning. Apply a penetrating grout sealer with a small brush, wipe the excess, and ventilate well. A mid-range 250 ml bottle costs £10–£15 and can cover multiple rooms. Sealing cuts water absorption and slows staining, which means less scrubbing later.
Curious about time and cost for a typical bathroom? A 5 m² wall area with 3 mm grout lines holds around 150–200 metres of grout. A single session uses 40–60 g of soda and about 30 minutes of steady work. Spread that over a year, and you are paying under £2 in materials and around six hours of calm, headphone-friendly cleaning. Many households will trade that for clearer lines and quieter air.
There are limits where professionals add value. Cracked grout needs raking out and regrouting. Deep, recurring mould suggests hidden leaks or exhausted ventilation. If tiles wobble or the seal at the bath edge lifts, address the structure first. The paste cleans; it does not repair. Use it as a maintenance ritual after you fix the root cause.
For readers who like numbers, the 3:1 ratio is forgiving. If the paste slumps, add a little more soda; if it crumbles, add a teaspoon of warm water. Keep sections small, allow the dwell, and give the final wipe your attention. That sequence delivers the result Peter championed: grout that looks like it belongs, not grout that shouts.
